ĐÁNH GIÁ TÌNH TRẠNG TƯỚI MÁU VI MẠCH NÃO TRÊN ĐỘNG VẬT THỰC NGHIỆM BỊ SAY NÓNG

Abstract

Objectives: To investigate the relationship between cerebral microcirculatory perfusion and hyperthermia in experimental rats. Methods: 10 adult Wistar rats were randomly assigned to a control group or a heat‑stroke group (HS group). Heat stroke was induced in the HS group by exposure to an environmental chamber at 43°C and 80% relative humidity until signs of heat shock appeared. Cerebral microvascular perfusion was measured via Laser-Doppler Flowmetry (LDF) through a small cranial burr hole. Biochemical and hematological parameters were assessed immediately before death. Results: Under hot‑humid conditions, rats in the HS group exhibited a rapid and significant increase in core temperature compared to those in the control group. The heart rate in the HS group rose progressively over time, and its LF/HF ratio was higher than that in the control group. ECG parameters in the HS group showed significant changes from the 30^th minute (R‑wave amplitude). Hematology revealed elevated RBC, hemoglobin, and hematocrit, with decreased MCHC and granulocyte. AST, ALT, and urea increased, while creatinine remained unchanged. SpO₂ decreased significantly from  the 60^th to the 90^th minute. BSC rose progressively and differed from the control group from the 30^th minute onward, whereas LDF perfusion decreased after 90 minutes. Conclusion: In heat‑stroked rats, hyperthermia induces an increase in laser BSC and a decrease in SpO₂. LDF‑measured cerebral microvascular perfusion tended to decline, though the change did not reach statistical significance, reflecting erythrocyte hemoconcentration and microcirculatory dysfunction in the brain.